How to Use Force Plates in Sports
There was a time not too long ago that force plates could be found only in engineering or biomechanics labs on university campuses. Today, however, there are a growing number of MLB organizations that either have installed them in their weight room, training room or performance center or have contracts with outside groups that use them to help determine physical and movement strengths and weaknesses, prescribe corrective programs, evaluate mechanics, etc. With the growing interest in force plates among MLB strength coaches and trainers, PBSCCS asked Pete Leno, an authority on the use of force plates in collegiate and professional sports, to explain some of the ways that force plates can be used in professional baseball. Associate Professor and Director of Human Performance Center at Dickinson State University, Dickinson, ND.
Coaching has always been and always will be part science and part art. For today’s coach, the science looks a little different than in the past. The use of Force Plates as part of the envelope of athlete development and care is becoming more common. Force Plates are the “Gold Standard” for the measurement of Force Production, Power, and Landing Dynamics in human movement. Today’s Sport Scientists and Sports Medicine professionals know that reliable measurements of 3-dimensional forces are essential to monitor performance, assess potential risk of lower extremity injury, and track the effect of training interventions.
What is a force plate/platform and how is it used? A force plate or platform is designed to continuously measure the force exerted on it. Forces in four perpendicular directions: vertical, horizontal, anterior-posterior (front and back) and medial-lateral (inside to outside) are usually plotted against time. Measuring forces applied by an athlete provides value to the coach for any or all the following reasons:
- Allows a quick and reliable assessment of how an athlete applies force when accelerating or decelerating his/her Center of Mass
- Well-designed protocols allow for quick and repeatable measurement during standard athletic movements
- A useful force plate analysis will provide coaches and trainers with baselines for detecting subtle differences in athletes over time. Typical uses include:
- Basic Movement Screen
- Neuromuscular Readiness
- Recovery over time
- Return to play decisions
- Dual Force Plates allow for detection of asymmetry when generating force and provide coaches and trainers with immediate actionable data
- Allow precise measurement of force trajectory
Force plates are tools that display what the coach’s eye can’t see. They don’t replace the coach’s eye, they enhance it.
More questions arise regarding which data are immediately actionable. Initially, coaches often make decisions based on their gut and the eye test, then gleam information from historical data, and finally they trust the data to help them make real time decisions. Too often, as coaches, we get focused on trying to collect data, but once we have it, we are not sure how we can use it to improve our decision making.
Keys for Effective Athlete Testing with Force Plates. The most fundamental application of a force plate analysis involves noting how an athlete changes over time. Thus, a primary focus with force plate testing should be establishing baseline values for each athlete. Deviations from baseline values are the essence of useful athlete monitoring and provide the most value to coaches and trainers. Deviations from baseline values can be used to help make decisions concerning performance, readiness and return to play situations.
Many products exist to quantify stress applied to the athletes (heart rate, GPS, etc.). Force plate data provide excellent insight into the effects of the stress on each athlete. Regular testing allows the staff to connect force plate data with other metrics to observe developing trends within each athlete. This provides coaches with a method for evaluating the effect of all loads applied, ultimately allowing them to define their own best practices for his/her athlete development model.
Important points to consider when designing a baseline testing protocol include:
- Clearly Defined Purpose: The primary focus with force plate testing should be establishing baseline values for each athlete. The baseline testing procedure should address questions that can be answered through your testing protocols. The best coaches and scientists are the ones who can ask relevant questions that can be answered with data.
- A consistent and repeatable testing protocol. A consistent protocol will allow you to establish valid baseline values for each athlete. My suggestion is to begin testing with a limited number of tests and limit the variables of interest to those you feel have the most immediate value. As your testing needs evolve, you can expand the number of tests and variables. Each test should take no more than 45-60 seconds per athlete. Testing 1-2x per month should be adequate during the season.
- Reliable Measures: Reliability is the consistency or reproducibility of measurements, i.e., do you get the same results. When deciding upon which tests and variables to use, select those with VERY high reliability of the data (ICC= .90+). A force plate analysis will be more reliable if the movement phases are well defined. To do so requires a reliable calculation of velocity rather than making assumptions of the direction the body is moving based solely on the force signal. If you want to measure an athlete’s ability to decelerate, you need to be certain which direction the center of mass is moving.
- Relevant Measures: Is force generated by the athlete impacting movement in a meaningful way! Force drives motion; thus, relevant measures will not only quantify force but reliably quantify the effect of that force on the athlete’s motion. Much of the research in exercise science and strength has shown the importance of measuring force, power and work output profiles during rather simple movements. Force plate analysis allows the user to better understand an athlete’s capabilities during a dynamic movement sequence and has the benefit of excellent day to day reliability.
- NO BLACK BOX ANALYSIS: Remember that you and your staff are the experts regarding the training of professional athletes. You should be making the training and recovery decisions for your athletes. The collection of force plate data should be part of a dynamic process to continually answer your current questions and drive you to ask the next question. A “Black Box” analysis implies that all the questions have been answered. Don’t get caught chasing red herring.
Pete Leno, MS is Associate Professor, Director of Human Performance Center and offensive line coach at Dickinson State University, Dickinson, ND. He has helped develop testing protocols and software associated with the use of force plates for use by collegiate and professional athletes in baseball, football and men’s and women’s soccer. To contact Pete for more information and research using force plates, go Peter.Leno@dickinsonstate.edu or skype pleno34.